Update 7 p.m. EDT 9/20: Friday’s first race was abandoned because the boats failed to complete the course under the 40-minute time limit. Oracle Team USA won the second race. New Zealand leads the regatta 8 to 3. Races 14 and 15 (if necessary) are scheduled for Saturday afternoon at 1:15 p.m. and 2:15 p.m. PDT, respectively.

Update 6:00 p.m. EDT 9/19: Thursday’s second race was postponed because wind speeds once again exceeded the 20-knot wind limit, according to Regatta Director Iain Murray. Races 13 and 14 are is scheduled for Friday at 1:15 p.m. and 2:15 p.m. PDT, respectively.

The high-tech U.S. racing team is on the verge of losing the America’s Cup, the world’s most famous sailboat racing competition, to Emirates Team New Zealand, in what would be a bitter defeat for Silicon Valley billionaire Larry Ellison, who spent an estimated $100 million on the American effort.

The New Zealanders need just two more race victories to clinch the venerable Auld Mug, one of the oldest continuously contested trophies in sports. Oracle is scheduled to meet New Zealand for two races on San Francisco Bay on Tuesday afternoon. The Kiwis currently lead the regatta 7-1 after splitting Sunday’s two races with Oracle. On Saturday, New Zealand had a breathtakingly close call, nearly capsizing their boat in heavy wind after a botched maneuver on the third leg of the race (see video below).

The two teams are competing in futuristic, 72-foot catamarans, which have two thin hulls, unlike the heavier, single-hulled boats that were used during most of the America’s Cup’s 162-year history. With their 131-foot carbon fiber wing sails, the AC72s are capable of reaching nearly 50 miles per hour — faster than the speed limit on the Golden Gate Bridge — while flying feet above the water on thin underwater foils, called daggerboards, which lift the boats out of the water, reducing drag and increasing speed.

“This is sailing like we’ve never seen before,” Ken Read, president of North Sails and himself a world champion sailboat racer, said during Sunday’s race broadcast. “These guys are just wheeling these things around like it’s a dinghy out in a Tuesday night race at Barrington Yacht Club back in Rhode Island.” Gary Jobson, president of US Sailing until 2012 and a member of the America’s Cup Hall of Fame, has called the current America’s Cup “match racing on steroids.” Read and Jobson are both serving as broadcast commentators for the regatta. (Race schedule here; broadcast schedule here).

The Kiwis, led by their unflappable skipper Dean Barker, have thus far largely dominated Oracle Team USA, winning seven out of 10 races. (Oracle was docked two points for a pre-race infraction.) Sailboat racing is like a national religion in New Zealand, and thousands of Kiwis have crowded the docks in San Francisco to cheer on their countrymen. For most of the regatta, New Zealand has been faster, particularly on the crucial third leg of the racecourse, where the teams must zig-zag back and forth against the wind. Oracle Team USA skipper Jimmy Spithill acknowledged earlier in the regatta that New Zealand had an edge when the boats are racing up wind.

The Americans have also made crucial tactical errors, including a botched attempt at a so-called “foiling tack,” in which Oracle tried to make a sharp tacking turn while keeping its hulls out of the water during race five. The maneuver failed, and Oracle nearly stopped dead in its tracks, allowing the Kiwis to leverage their up wind advantage through savvy tactics and sheer boat speed.

In recent races, the Americans have closed the speed gap somewhat thanks to improved teamwork and tweaks in the boat’s configuration. The America’s Cup – like all “one-design” races – adheres to a strict design standard, in order to create a level playing field so the skill of the sailors will win the day, but minor design differences exist. The New Zealand catamaran’s hulls are slightly thicker than Oracle’s toward the bow, which allows the Kiwi boat to plow through the water, maintaining momentum as helmsman Barker executes tacking and gybing maneuvers.

Oracle Team USA was penalized two points in a cheating scandal during an earlier stage of the event, which means the Americans need to win 11 races, compared to nine races for the Kiwis. Oracle team-members were found to have placed illegal weights on their boats, a grave racing violation that the APcalled “the biggest cheating scandal in the 162-year-history of the America’s Cup.” Three Oracle team-members were banned from the event. Last week, Oracle replaced tactician John Kostecki — who had been one of only two Americans on the 11-man crew — with British Olympic star Sir Ben Ainslie.

Billionaire Oracle mogul Larry Ellison’s team won the America’s Cup in 2010 and thus earned the right to determine the current regatta’s rules. He called for the new AC72 catamaran, which can hydroplane on top of the water at speeds of nearly 50 miles per hour. These boats are among the fastest, most sophisticated, most expensive, and most dangerous sailboats ever built. One sailor, Andrew Simpson, died in training, prompting increased safety measures for the regatta.

First contested off England’s Isle of Wight in 1851, the America’s Cup has frequently been pursued by wealthy titans of industry with names like Vanderbilt, Lipton, Turner and, more recently, Bertarelli and Ellison. For years, America’s Cup organizers have struggled to make the event more accessible to a mass audience. The current regatta features groundbreaking technology developed by SportVision, which uses GPS positioning to superimpose graphics detailing boat, wind, and water speed during the television broadcasts. SportVision previously deployed the technology for NFL, MLB and NASCAR broadcasts.

For the last two decades, the America’s Cup has been in and out of federal court, as wealthy rival syndicates bickered over the competition’s rules. Ellison’s Oracle Team USA won the trophy in 2010, setting up the current regatta on San Francisco Bay between the Americans and the Kiwis. The cost and complexity of the AC72s — it takes as much $100 million to mount a campaign — kept many potential challengers from competing, prompting speculation that future America’s Cup events will be sailed on smaller, less expensive boats.

The dearth of competitors in this year’s America’s Cup prompted the Bay Area Council Economic Institute to reduce its forecast of the economic activity expected to be produced by the event from $1.4 billion to $900 million. “There are definitely going to have to be cost-saving measures to allow more teams to get into it,” Kiwi skipper Dean Barker told a press conference on Sunday.

Watch Emirates Team New Zealand nearly capsize their 72-foot catamaran during Race 8 on Saturday.